Abstract:

The physiological and biochemical responses of Pinus massoniana to low phosphorus stress were investigated in this study, and the different phosphorus concentrations of the treatments were conducted by using a single factor experiment with sand culture in the green house. Results showed that the increase of root-shoot ratio was an active adaptive response of P. massoniana to low phosphorus stress. Under the situation of low phosphorus stress, the concentrations of soluble sugar and free proline increased whereas the chlorophyll and soluble protein decreased. The decrease of chlorophyll and soluble protein would result in a decrease in net photosynthetic rate of P. massoniana. Thus the major factor affected the biomass of P. massoniana is the decrease of net photosynthetic rate and transpiration rate as well as the increased dark respiration rate. Moreover, the homeostasis established by the increase of MDA concent and protective enzyme (POD, SOD) activity in needles is the mechanism of the adaptive response for P. massoniana to low phosphorus stress.

Key words: Pinus massoniana, phosphorus stress, physiological responses, biochemical responses